Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
CERMET TOOL
TECHNICAL FIELD
[0001] The present invention relates to a cermet tool.
BACKGROUND ART
[0002] Cermet tools are excellent in reaction resistance with iron and high-
temperature
strength compared with cemented carbide tools, and they are used for finishing
process
with taking advantage of the properties. For example, Patent Literature 1
describes a
cermet tool having: a first hard phase with a core-rim structure composed of a
core
portion with a composite carbonitride phase of Ti, Nb, and Zr and a peripheral
portion
with a composite carbonitride phase of Ti, Nb, Zr and W or Ti, Nb, Zr, W and
Ta; and a
second hard phase with a core-rim structure composed of both a core portion
and a
peripheral portion with a composite carbonitride phase of Ti, Nb, Zr, and W or
a
composite carbonitride phase of Ti, Nb, Zr, W, and Ta.
PRIOR ART DOCUMENTS
Patent Document
[0003] Patent Literature 1: JP 2007-69311 A
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] However, in cutting process in recent years, higher speed, higher feed,
and
deeper cut became notable. In such high speed cutting conditions accompanied
by
heat generation at high temperatures, the tool life has tended to be reduced
compared to
conventional ones. That is, because strength between particles in the hard
phases is
insufficient, the conventional cermet tools have a problem of harshening
roughness of a
machined surface of a work piece material due to falling of hard phase
particles in high
speed cutting conditions accompanied by heat generation at high temperatures.
They
also have a problem of poor chipping resistance and fracture resistance while
having
excellent hardness of the hard phase.
[0005] The present invention has been made to solve the above problems. It is
an
object of the present invention to provide a cermet cutting tool that reduces
machined
surface roughness of a work piece material, has excellent fracture resistance
and
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excellent chipping resistance without reducing wear resistance, and has long
tool life.
Means to solve the Problems
[0006] The present inventor conducted various examinations on cermet tools. As
a
result, the present inventor found that improvement in hard phase composition
of a
cermet tool enables fabrication of a cermet tool that has excellent fracture
resistance and
excellent chipping resistance without reducing wear resistance and reduces
machined
surface roughness of a work piece material to reach the present invention.
[0007] That is, the summary of the present invention is as follows.
(1) A cermet tool includes: not less than 75 volume% and not more than 95
volume% of a hard phase; and not less than 5 volume% and not more than 25
volume%
of a binder phase, wherein
the hard phase is composed of
(a) a first hard phase with a core-rim structure composed of a core
portion with a composite carbonitride phase of Ti, Nb, and Mo and a peripheral
portion
with a composite carbonitride phase of Ti, Nb, Mo, W, and Zr [hereinafter,
referred to
as (Ti, Nb, Mo, W, Zr) (C, N)] or a composite carbonitride phase of Ti, Nb,
Mo, and W
[hereinafter, referred to as (Ti, Nb, Mo, W) (C, N)],
(b) a second hard phase with a core-rim structure composed of both a
core portion and a peripheral portion with the (Ti, Nb, Mo, W, Zr) (C, N)
phase or the
(Ti, Nb, Mo, W) (C, N) phase, and
(c) a third hard phase composed of a composite carbonitride phase of
Ti, Nb, and Mo,
the binder phase is composed of an element having at least one selected from
the group consisting of Co, Ni, and Fe as a main component,
when a maximum content of a concentration of the Nb element in a surface
region that is within a range from a surface of the cermet tool to a depth of
300 p.m is
Nbs and an internal content of a concentration of the Nb element in an
internal region
that is deeper inside from the surface region is Nbi, Nbs/Nbi is not less than
0.8 and not
more than 1.2,
when a maximum content of a concentration of the W element in the surface
region is Ws and an internal content of a concentration of the W element in
the internal
region is Wi, Ws/Wi is not less than 1.0 and not more than 1.5, and,
in a cross section of the internal region of the cermet tool, when an area
ratio of
the first hard phase is Al, an area ratio of the second hard phase is A2, an
area ratio of
the third hard phase is A3, and an area of the entire hard phase is 100 area%,
the Al is
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not less than 75 area% and not more than 95 area%, the A2 is not less than 4
area% and
not more than 24 area%, and the A3 is not less than 1 area% and not more than
24
area%.
(2) The cermet tool of (1), wherein, when Vickers hardness in the surface
region is Hs and Vickers hardness in the internal region is Hi, Hs/Hi is not
less than 1.1
and not more than 1.3.
(3) The cermet tool of (1) or (2), wherein, when an area ratio of the core
portion in the first hard phase in the surface region is Cls and an area ratio
of the core
portion in the first hard phase in the internal region is Cli, Cls/Cli is not
less than 0.3
and not more than 0.9.
(4) The cermet tool of any one of (1) to (3), wherein, when an average
particle
size of the hard phase in the surface region is ds and an average particle
size of the hard
phase in the internal region is di, ds/di is not less than 1.0 and not more
than 2Ø
(5) The cermet tool of any one of (1) to (4), wherein an average particle size
of
the hard phase is not less than 1.0 [tm and not more than 3.0 m.
(6) The cermet tool of any one of (1) to (5), wherein a part of Nb contained
in
the hard phase is substituted by Ta.
(7) A coated cermet tool includes: the cermet tool according to any one of (1)
to (6); and a coating layer formed on a surface of the cermet tool.
[0008] < Cermet Tool >
Specific examples of type of a cermet tool of the present invention include
indexable inserts for milling, or turning, drills, and end mills.
[0009] The cermet tool of the present invention is a cermet tool including a
hard phase
and a binder phase having at least one selected from the group consisting of
Co, Ni, and
Fe as a main component. The proportion of the hard phase to the entire cermet
tool
(100 volume%) is from 75 to 95 volume% and the binder phase occupies the rest.
[0010] When the proportion of the hard phase is less than 75 volume% in the
cermet
tool of the present invention, the wear resistance of the cermet tool is
reduced. When
the proportion of the hard phase is over 95 volume% in the cermet tool of the
present
invention, the fracture resistance of the cermet tool is reduced and the
residual amount
for the binder phase is also reduced relatively, so that sinterability of raw
materials is
reduced during production of the cermet tool. Therefore, the proportion of the
hard
phase is determined from 75 to 95 volume% and the proportion of the binder
phase as
the rest. From the above perspective, it is even more preferred that the
proportion of
the hard phase is from 80 to 90 volume% and the proportion of the binder phase
takes
the rest.
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[0011] The proportions of the hard phase and the binder phase in the cermet
tool of the
present invention are obtained as follows. A cross-section from a surface of
the cermet
tool to 500 [tm inside in a depth direction is observed with a scanning
electron
microscope (SEM) with an energy dispersive X-ray spectrometer (EDS), and the
cross-section is chemically etched using aqua regia to observe the chemically
etched
cross-section with a SEM with an EDS. Then, from these two types of cross-
section,
an area ratio of the hard phase that is not chemically etched and an area
ratio of the hard
phase that is chemically etched are measured. From the measured results,
proportions
of volume% of the hard phase and volume% of the binder phase in the cermet
tool are
obtained.
[0012] The binder phase of the cermet tool of the present invention is metal
having at
least one selected from Co, Ni, and Fe as a main component. The metal having
at least
one selected from Co, Ni, and Fe as a main component means metal in which
total mass
of metal at least one selected from Co, Ni, and Fe in the binder phase is 50
mass% or
more based on the total mass of the binder phase. In the binder phase of the
present
invention, other than Co, Ni, and Fe, hard phase components may be contained.
Generally, the total content of the hard phase component contained in the
binder phase
of the present invention is 20 mass% or less based on the total mass of the
binder phase.
In particular, it is more preferred that the binder phase of the cermet tool
of the present
invention is metal having one or two of Co and Ni as main components. In such
a case,
it is possible to obtain a cermet tool that is excellent in wettability
between the binder
phase and the hard phase, heat resistance, and corrosion resistance.
[0013] The hard phase of the cermet tool of the present invention has a first
hard phase
with a core-rim structure composed of a core portion with a composite
carbonitride
phase of Ti, Nb, and Mo [hereinafter, referred to as (Ti, Nb, Mo) (C, N)] and
a
peripheral portion with a composite carbonitride phase of Ti, Nb, Mo, W, and
Zr
[hereinafter, referred to as (Ti, Nb, Mo, W, Zr) (C, N)] or a composite
carbonitride
phase of Ti, Nb, Mo, and W [hereinafter, referred to as (Ti, Nb, Mo, W) (C,
N)]. The
core portion and the peripheral portion have different composition. Since Nb
is
excellent in high-temperature hardness and oxidation resistance, wear by
reaction is
inhibited in high speed process and thus the cermet tool has excellent wear
resistance.
Mo is excellent in wettability with the binder phase during sintering and also
excellent
in wettability between the hard phases. The strength of the cermet tool is
therefore
improved by containing Mo in the first hard phase, and thus the fracture
resistance and
chipping resistance are improved. Further, W is excellent in hardness. The
cermet
tool therefore has excellent wear resistance by containing W in the first hard
phase. In
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addition, Zr in the hard phase is excellent in high-temperature strength, so
that the
cermet tool has excellent plastic deformation resistance by containing Zr in
the first
hard phase.
[0014] The hard phase of the cermet tool of the present invention has a second
hard
phase with a core-rim structure composed of both a core portion and a
peripheral
portion with a (Ti, Nb, Mo, W, Zr) (C, N) phase or a (Ti, Nb, Mo, W) (C, N)
phase. W
is excellent in hardness. The cermet tool is therefore excellent in wear
resistance by
containing W in the second hard phase. In addition, Zr in the hard phase is
excellent in
high-temperature strength, so that the cermet tool has excellent plastic
deformation
resistance by containing Zr in the second hard phase.
[0015] The hard phase of the cermet tool of the present invention has a third
hard
phase with a single phase particle structure composed of a composite
carbonitride phase
of Ti, Nb, and Mo [hereinafter, referred to as (Ti, Nb, Mo) (C, N)]. The third
hard
phase is excellent in thermal shock resistance due to high thermal
conductivity, so that it
is possible to inhibit generation of thermal cracks. By having the third hard
phase
dispersed in the cermet tool, the fracture resistance is therefore improved.
[0016] In particular, the cermet tool of the present invention contains Nb and
Mo in all
the hard phase of the first hard phase, the second hard phase, and the third
hard phase,
so that the tool is excellent in wear resistance at high temperatures and also
excellent in
fracture resistance. In addition, Ta is excellent in high-temperature hardness
similar to
Nb. Therefore, the cermet tool of the present invention is also
preferred to substitute
Ta for a part of Nb contained in the hard phase within at least one hard phase
of the hard
phases constituting the first hard phase, the second hard phase, and the third
hard phase.
[0017] In the cermet tool of the present invention, when a maximum content of
a
concentration of the Nb element in a surface region that is within a range
from a surface
of the cermet tool to a depth of 300 lam is Nbs and an internal content of a
concentration
of the Nb element in an internal region that is deeper inside from the surface
region is
Nbi, Nbs/Nbi is not less than 0.8 and not more than 1.2. When Nbs/Nbi falls
within
this range, the concentration of the Nb element is approximately uniform in
the surface
region and the internal region of the cermet tool, so that the cermet tool has
excellent
high-temperature strength. When Nbs/Nbi is less than 0.8, the wear resistance
of the
cermet tool is reduced. When Nbs/Nbi is over 1.2, the fracture resistance of
the cermet
tool is reduced.
[0018] In the cermet tool of the present invention, when a maximum content of
a
concentration of the W element in a surface region that is within a range from
a surface
of the cermet tool to a depth of 300 [tin is Ws and an internal content of a
concentration
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of the W element in an internal region that is deeper inside from the surface
region is
Wi, Ws/Wi is not less than 1.0 and not more than 1.5. When Ws/Wi falls within
this
range, hardness in the surface region of the cermet tool is excellent and
toughness in the
internal region is excellent, and thus the wear resistance, the chipping
resistance, and
the fracture resistance of the cermet tool are improved. When Ws/Wi is less
than 1.0,
the wear resistance of the cermet tool is reduced. When Ws/Wi is over 1.5, the
chipping resistance and the fracture resistance of the cermet tool are
reduced.
[0019] In the cermet tool of the present invention, by having a uniform
concentration
of the Nb element in the surface region and the internal region, and
increasing the
concentration of the W element in the surface region, cutting performances,
such as
wear resistance, chipping resistance, and fracture resistance, are improved.
That is, Nb
with excellent in high-temperature hardness contributes to the cutting
performances in
high speed cutting conditions accompanied by heat generation at high
temperatures,
whereas W contributes to the cutting performances in conventional cutting
conditions.
It is, therefore, possible to process without reducing the cutting
performances in all
process conditions.
[0020] In the cermet tool of the present invention, in a cross section of the
internal
region that is deeper inside from the surface region that is within a range
from a surface
of the cermet tool to a depth of 300 ilM, when an area ratio of the first hard
phase is Al,
an area ratio of the second hard phase is A2, an area ratio of the third hard
phase is A3,
and an area of the entire hard phase is 100 area%, the Al is not less than 75
area% and
not more than 95 area%, the A2 is not less than 4 area% and not more than 24
area%,
and the A3 is not less than 1 area% and not more than 24 area%. When Al is
less than
75 area%, toughness is insufficient and thus the fracture resistance of the
cermet tool is
reduced. When Al is over 95 area%, the area of A2 or A3 is relatively reduced
and
thus the hardness or thei __ Ina' conductivity is reduced, so that the wear
resistance or the
theimal shock resistance of the cermet tool is reduced. When A2 is less than 4
area%,
hardness is insufficient and thus the wear resistance of the cermet tool is
reduced.
When A2 is over 24 area%, the area of Al or A3 is relatively reduced and thus
the
toughness and the thermal conductivity are reduced, so that the fracture
resistance or the
thermal shock resistance of the cermet tool is reduced. When A3 is less than 1
area%,
thermal conductivity is insufficient and thus the thermal shock resistance of
the cermet
tool is reduced. When A3 is over 24 area%, the area of Al or A2 is relatively
reduced
and thus the toughness is reduced, so that the fracture resistance of the
cermet tool is
reduced.
[0021] In the cermet tool of the present invention, when Vickers hardness in
the
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surface region that is within a range from a surface of the cermet tool to a
depth of 300
tm is Hs and Vickers hardness in the internal region that is deeper inside
from the
surface region is Hi, Hs/Hi is preferably not less than 1.1 and not more than
1.3. When
Hs/Hi of the cermet tool of the present invention is less than 1.1, the wear
resistance
tends to be reduced. When Hs/Hi is over 1.3, the chipping resistance and the
fracture
resistance tend to be reduced.
[0022] In the cermet tool of the present invention, when an area ratio of the
core
portion in the first hard phase in the surface region that is within a range
from a surface
of the cermet tool to a depth of 300 ?Am is Cis and an area ratio of the core
portion in
the first hard phase in the internal region that is deeper inside from the
surface region is
Cli, Cls/Cli is preferably not less than 0.3 and not more than 0.9. When
Cls/Cli of
the cermet tool of the present invention is less than 0.3, the fracture
resistance tends to
be reduced. When Cls/Cli is over 0.9, the wear resistance tends to be reduced.
[0023] In the cermet tool of the present invention, when an average particle
size of the
hard phase in the surface region that is within a range from a surface of the
cermet tool
to a depth of 300 p.m is ds and an average particle size of the hard phase in
the internal
region that is deeper inside from the surface region is di, ds/di is
preferably not less than
1.1 and not more than 2Ø When ds/di of the cermet tool of the present
invention is
less than 1.1, the fracture resistance tends to be reduced. When ds/di is over
2.0, the
wear resistance tends to be reduced.
[0024] In the cermet tool of the present invention, an average particle size
of the hard
phase is preferably not less than 1.0 pm and not more than 3.01.1m. When the
average
particle size of the hard phase in the cermet tool of the present invention is
less than 1.0
vim, the fracture resistance tends to be reduced. When the size is over 3.0
tm, the
hardness is reduced and the wear resistance tends to be reduced.
[0025] The concentration of the Nb element and the concentration of the W
element in
the cermet tool of the present invention are obtained as follows. The cermet
tool is
polished by tilting at 10 degrees relative to the surface of the cermet tool
and the
cross-section of the polished surface is observed with an SEM, and the
concentration is
obtained by using the EDS attached to the SEM. Concentrations in 10 spots with
intervals of 10 i_tm in a vertical direction from the surface of the cermet
tool are
measured and the maximum contents among them are defined as Nbs and Ws, and
arbitrary concentrations in 10 spots in positions of 5001..im from the surface
are
measured and the average values are defined as Nbi and Wi.
[0026] Vickers hardness Hs in the surface region of the cermet tool of the
present
invention and Vickers hardness Hi in the internal region are obtained as
follows. In
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order to measure hardness from the surface to inside of the cermet tool, the
cermet tool
is polished by tilting at 10 degrees relative to the surface of the cermet
tool to measure
Vickers hardness at an applied load of 4.9 N using a micro-Vickers hardness
tester with
intervals of 10 pm in the vertical direction from the surface of the cermet
tool. The
maximum hardness in a range within 300 jim from the surface of the cermet tool
is
defined as Hs, and Vickers hardness in 5 spots in positions of 500 um from the
surface
of the cermet tool are measured and the maximum hardness among the 5 spots is
defined as Hi.
[0027] The average particle size ds in the surface region and the average
particle size
di in the internal region of the hard phase of the cermet tool of the present
invention are
obtained as follows. The cermet tool is polished by tilting at 10 degrees
relative to the
surface of the cermet tool. The sizes are obtained from an image of the cross-
section
of the polished surface enlarged at a magnification from 2000 to 10000 with an
SEM
using Fullman's expression (1).
dm = (4/7) = (NL/NS) (1)
(In the equation, dm denotes an average particle size, it denotes the circular
constant,
NL denotes the number of hard phases per unit length hit by an arbitrary
straight line on
the cross-section, and NS denotes the number of hard phases contained in an
arbitrary
unit area.)
The average particle size of the hard phase is a value obtained by averaging
the
average particle size ds in the surface region and the average particle size
di in the
internal region.
[0028] The area ratios Al, A2, and A3 of the respective hard phases in the
internal
region of the cermet tool of the present invention are obtained from an SEM
image of
the cross-section by a method using commercially available image analysis
software or
the method using Fullman's expression. A specific measurement method when
Fullman's expression is used is described below. The cermet tool is polished
and the
ratio is obtained from an image of the cross-section of the polished surface
in the
internal region of the cermet tool enlarged at a magnification from 2000 to
10000 with
an SEM using the Fullman's expression (1). Using the Fullman's expression (1)
described above, the respective average particle sizes of the first hard
phase, the second
hard phase, and the third hard phase are obtained. Using the average particle
size of
each hard phase and the number of each hard phase contained in the unit area,
the area
of each hard phase contained in the unit area is obtained and the area ratios
Al, A2, and
A3 of the respective hard phases are determined.
[0029] The area ratio Cls of the core portion in the first hard phase in the
surface
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region of the cermet tool of the present invention and the area ratio Cli of
the core
portion in the first hard phase in the internal region are obtained as
follows. The
cermet tool is polished by tilting at 10 degrees relative to the surface of
the cermet tool.
A photograph of the polished sectional surface is taken by enlarging at a
magnification
from 2000 to 10000 with an SEM. Cis and C li are calculated from the
photograph
using commercially available image analysis software.
Effects of the Invention
[0030] The cermet tool of the present invention enables reduction of machined
surface
roughness of a work piece material. In addition, the cermet tool of the
present
invention has excellent fracture resistance and excellent chipping resistance
without
reducing wear resistance, so that the tool exhibits the effect of extending
tool life more
than conventional ones.
EXAMPLES
[0031] Subsequently, a method of manufacturing a cermet tool of the present
invention is described using specific examples. The method of manufacturing a
cermet tool of the present invention is not limited in particular as long as
the structure
(the hard phase and the binder phase) of the cermet tool is achieved.
[0032] For example, a method of manufacturing a cermet tool of the present
invention
includes:
step (A): a step of blending 30 to 90 mass% of titanium niobium molybdenum
carbonitride powder or titanium niobium tantalum molybdenum carbonitride
powder
having an average particle size of 0.5 to 4.0 jAm, 5 to 40 mass% of at least
one type of
powder, having an average particle size of 0.5 to 4.0 i_tm, selected from the
group
consisting of a carbide, a nitride, and a carbonitride of at least one metal
element
selected from the group consisting of Ti, Zr, Nb, Mo, and W except titanium
niobium
molybdenum carbonitride and titanium niobium tantalum molybdenum carbonitride
powder, and 5 to 30 mass% of at least one type of powder selected from the
group
consisting of Co, Ni, and Fe having an average particle size of 0.5 to 3.0 [an
(note that
they are 100 mass% in total);
step (B): a mixing step of blending the raw material powder and mixing in a
wet ball mill in 5 to 35 hours to prepare a mixture;
step (C): a pressing step of obtaining a pressed body by pressing the mixture
to
form a predetermined shape of a tool;
step (D): a first temperature-increasing step of increasing temperature of the
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pressed body obtained in the step (C) to a predetermined temperature within a
range
between 1200 and 1400 C in vacuum at 67 Pa or less;
step (E): a second temperature-increasing step of increasing temperature of
the
pressed body after the step (D) to a sintering temperature within a range
between 1400
and 1600 C, from the predetermined temperature within a range between 1200 and
1400 C, (the sintering temperature is higher than the predetermined
temperature) in a
nitrogen atmosphere from 50 to 1330 Pa;
step (F): a first sintering step of maintaining the pressed body after the
step (E)
at a sintering temperature within the range between 1400 and 1600 C in a
nitrogen
atmosphere at the pressure same as the pressure in the step (E) for a
predetermined
period of time for sintering;
step (G): a first cooling step of cooling the pressed body after the step (F)
to a
temperature within a range between1000 and 1200 C at a rate of 1 to 50 C/min
from the
range between 1400 and 1600 C in a nitrogen pressure from Ito 50 Pa that is
lower
than the pressure in the step (F);
step (H): a second sintering step of maintaining the pressed body after the
step
(G) at a sintering temperature within a range between1000 and 1200 C in a
nitrogen
atmosphere at the pressure same as the pressure in the step (G) for a
predetermined
period of time for sintering; and
step (I): a second cooling step of cooling the pressed body after the step (H)
from the predetermined temperature within the range between1000 and 1200 C to
normal temperature.
[0033] The raw material powder used in the step (A) has an average particle
size
measured by Fisher method (Fisher Sub-Sieve Sizer (FSSS)) in accordance with
American Society for Testing Materials (ASTM) standard B330.
[0034] Each step of the method of manufacturing a cermet tool of the present
invention has the following significance.
In the step (A), the use of titanium niobium molybdenum carbonitride powder
or titanium niobium tantalum molybdenum carbonitride powder and at least one
type of
powder selected from the group consisting of a carbide, a nitride, and a
carbonitride of
at least one metal element selected from the group consisting of Ti, Zr, Nb,
Mo, and W
enables constitution of the first hard phase, the second hard phase, and the
third hard
phase.
[0035] In the step (B), it is possible to adjust the average particle size of
the hard
phase and unifoinily mix the mixed powder with predetermined composition. This
is
pressed, sintered, and cooled in the following steps to obtain the cermet tool
of the
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present invention having a hard phase and a binder phase with specific
composition.
[0036] In the step (C), the mixture thus obtained is pressed to form a
predetermined
shape of a tool. The pressed body thus obtained is sintered in the following
sintering
step.
[0037] In the step (D), the temperature of the pressed body is increased in
vacuum at
67 Pa or less to accelerate degasification before appearance of a liquid phase
and
immediately after appearance of a liquid phase, and thus the sinterability in
the
following sintering step is improved.
[0038] In the step (E), sintering at a temperature within a range between 1400
and
1600 C enables an increase in the concentration of the W element in the
surface region
of the cermet tool. In addition, in the steps (E) and (F), the process is
performed in the
nitrogen atmosphere to prevent denitrification from the surfaces of the
pressed body.
Therefore, reduction of smoothness on the as-sintered surface accompanied by
denitrification and reduction in the hard phase, such as (Ti, Nb, Mo) (C, N),
near the
as-sintered surface are inhibited.
[0039] In the step (G), cooling at a nitrogen pressure of 1 to 50 Pa that is
lower than
the steps (E) and (F) and at a cooling rate from 1 to 50 C/min enables
inhibition of
movement of Nb elements to the surfaces of the pressed body.
[0040] In the step (H), by holding at a temperature lower than that in the
step (F), the
area ratios of the first to third hard phases become arbitrary.
[0041] Then, in the step (I), the sintered body is cooled to room temperature
to obtain
the cermet tool of the present invention.
[0042] The cermet tool obtained through the steps from (A) to (I) may be
subjected to
grinding and honing on the edge, as needed.
Example 1
[0043] [Production of Cermet Tool]
As raw material powders that were commercially available, (Ti, Nb, Mo) (C,
N) powder having an average particle size of 2.0 pm (mass ratio of TiC/TiN =
50/50),
(Ti, Nb, Ta, Mo) (C, N) powder having an average particle size of 2.0 tm (mass
ratio of
TiC/TiN = 50/50), WC powder having an average particle size of 1.5 jim, ZrC
powder
having an average particle size of 1.5 [im, Co powder having an average
particle size of
1.0 i.tm, and Ni powder having an average particle size of 1.0 in were
prepared. The
average particle sizes of the raw material powders were measured by Fisher
method
(Fisher Sub-Sieve Sizer (FSSS)) in accordance with American Society for
Testing
Materials (ASTM) standard B330. The expression (Ti, Nb, Mo) (C, N) means
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composite carbonitride of Ti, Nb, and Mo and (Ti, Nb, Ta, Mo) (C, N) means
composite
carbonitride of Ti, Nb, Ta, and Mo.
[0044] The prepared raw material powders were weighed to be at the blending
composition in Table 1 below, and the weighed raw material powders were put in
a
stainless steel pot together with an acetone solvent and cemented carbide
balls for
mixing and grinding in the wet ball mill. Time periods for mixing and grinding
in the
wet ball mill are shown in Table 2. After the mixing and grinding in the wet
ball mill,
the mixture obtained by evaporating the acetone solvent was pressed at a
pressure of
196 MPa in a mold to be, after sintering, a shape of an insert shape of
SDKN1203 with
a breaker in JIS B 4120, and a pressed body of the mixture was obtained.
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[0045] [Table 1]
Sample No. Composition (mass %)
Present 60% (Ti0,80Nbo.loMoo.io) (C0.5N0.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 1
Present 70% (Ti0.80NbooloMoo.io) (C0.51\10.5), 11%WC, 1%ZrC, 9%Co, 9%Ni
Product 2
Present 50% (Ti0.80Nbo.i0Moo.io) (Co.5N0.5), 33%WC, 1%ZrC, 8%Co, 8%Ni
Product 3
Present 60% (Tio.70Nb0.20Mo0.10) (C0.51\10.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 4
Present 60% (Ti0.90Nbo.08Moo.02) (C0.5N0.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 5 ________
Present 65% (Ti0.80Nbo.loMoo.io) (C0.5N0.5), 22%WC, 1%ZrC, 6%Co, 6%Ni
Product 6
Present 53% (Ti0.80Nb0.10Moo.io) (C0.5N0.5), 22%WC, 1%ZrC, 12%Co, 12%Ni
Product 7
Present 60% (Ti0.80Nbo.10Moo.io) (C0.5N0.5), 22%WC, 1%ZrC, 12%Co, 5%Ni
Product 8
Present 60% (Ti0.80Nb0.10Moo.io) (Co.5N0.5), 22%WC, 1%ZrC, 5%Co, 12%Ni
Product 9
Present 60%(Ti0.70Nbo.10 Ta0.10Moo.io) (C0.5N0.5), 20%WC, 1%ZrC, 10%Co,
Product 10 9%Ni
Comparative 60% (Ti0.800Nb0.10M00.0 (Co.51\10.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 1
Comparative 60% (Tio.801\1110.10M00.10) (C0.5N0.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 2
Comparative 50%Ti(C0.5N0.5), 22%WC, 8%NbC, 1%Mo, 2%C, 1%ZrC, 9%Co,
Product 3 9%Ni
Comparative 60% (Ti0.80Nbo.i0Moo.io) (C0.51=10.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 4
Comparative 60% (Ti0.80Nb0.10Moo.10) (C0.51\10.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 5
Comparative 60% (Tio.80Nb0.10Moo.lo) (C0.5N0.5), 21%WC, 1%ZrC, 9%Co, 9%Ni
Product 6
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[0046] [Table 2]
Sample No. Time Period In Wet Ball Mill (hours)
Present Product 1 13
Present Product 2 12
Present Product 3 15
Present Product 4 13
Present Product 5 13
Present Product 6 12
Present Product 7 15
Present Product 8 13
Present Product 9 14
Present Product 10 14
Comparative Product 1 13
Comparative Product 2 30
Comparative Product 3 15
Comparative Product 4 13
Comparative Product 5 14
Comparative Product 6 13
[0047] After the pressed body of the mixture was put in a sintering furnace,
the
temperature was increased to a nitrogen introduction temperature Ti ( C) shown
in
Table 3(a) from room temperature in vacuum at 67 Pa or less. When the
temperature
in the furnace reached the nitrogen introduction temperature Ti ( C), nitrogen
gas was
introduced into the sintering furnace until a pressure in the furnace reached
a furnace
pressure P1 (Pa) shown in Table 3(b). In the nitrogen atmosphere at the
furnace
pressure P1 (Pa), the temperature was increased from the nitrogen introduction
temperature T1 ( C) to the sintering temperature 12 ( C) shown in Table 3(c).
When
the temperature in the furnace reached the sintering temperature T2 ( C), the
sintering
temperature T2 ( C) was maintained in the nitrogen atmosphere at the furnace
pressure
P1 (Pa) for 60 mm. for sintering. Then, the nitrogen gas was discharged until
the
furnace pressure P1 (Pa) reached a furnace pressure P2 (Pa) shown in Table
3(d), and
then it was cooled from the sintering temperature T2 ( C) to a sintering
temperature T3
( C) shown in Table 3(f) with a cooling rate R1 ( C/min.). When the
temperature in
the furnace reached the sintering temperature T3 ( C), the sintering
temperature T3 ( C)
was maintained in the nitrogen atmosphere at the furnace pressure P2 (Pa) for
60 min.
for sintering. Then, the nitrogen was discharged and replaced by an argon
atmosphere.
The argon atmosphere was cooled from the sintering temperature T3 ( C) to room
temperature.
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[0048] [Table 3]
Sample No. (a) (b) (c) (d) (e) (f)
Nitrogen Pressure in Sintering Pressure in Cooling
Sintering
Introduction Furnace Temperature Furnace Rate Temperature
Temperature P1 (Pa) T2 ( C) P2(Pa) R1 T3 ( C)
Ti ( C) ( C /min)
_
Present 1350 200 1550 30 10 1150
-Product 1
Present 1300 200 1500 30 10 1100
- Product 2
Present 1400 200 1600 30 10 1200
Product 3
Present 1350 200 1550 30 10 1150
Product 4
Present 1350 - 200 1550 30 50 1150
Product 5
Present 1350 200 1550 30 5 1150
Product 6
Present 1350 200 1550 5 10 1150
Product 7
Present 1350 500 1550 30 10 1150
Product 8
Present 1350 200 1550 50 10 1150
Product 9
Present 1380 200 1550 40 10 1170
Product 10
Comparative 1400 200 1650 30 10 1250
Product 1
Comparative 1250 200 1380 30 10 1150
Product 2
Comparative 1350 200 1550 30 10 1150
Product 3
Comparative 1400 200 1650 100 10 1150
Product 4
Comparative 1400 200 1650 1 100 1250
Product 5
Comparative 1350 200 1550 - - -
Product 6
[0049] The cermet tool obtained by sintering was subjected to honing at the
edge of
the cermet tool by a wet brush honing machine.
[0050] The cermet tools of Present Products and Comparative Products thus
prepared
were polished by tilting at 10 degrees relative to surfaces of the cermet
tools.
Cross-sections of the polished surfaces were observed with an SEM to measure
each
composition of Nbs and Ws in the surface region and Nbi and Wi in the internal
region,
respectively, using the EDS attached to the SEM. From the compositions thus
measured, Nbs/Nbi and Ws/Wi were obtained. The results are shown in Table 4.
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[0051] [Table 4]
Sample No. Nbs/Nbi Ws/Wi
Present Product 1 0.9 1.1
Present Product 2 1.0 1.0
Present Product 3 0.8 1.4
Present Product 4 0.9 1.1
Present Product 5 0.9 1.0
Present Product 6 1.0 1.1
Present Product 7 1.1 1.1
Present Product 8 1.1 1.5
Present Product 9 1.0 1.0
Present Product 10 1.0 1.1
Comparative Product 1 1.1 1.4
Comparative Product 2 1.1 0.9
Comparative Product 3 1.5 1.5
Comparative Product 4 1.1 1.3
Comparative Product 5 0.9 1.6
Comparative Product 6 1.4 1.3
[0052] For the polished surface polished by tilting at 10 degrees relative to
a surface of
the cermet tool, an image of a cross-section of the polished surface enlarged
at a
magnification of 5000 with an SEM was taken. From the image thus taken, the
average particle size ds in the surface region of the hard phase and the
average particle
size di in the internal region were measured using Fullman's expression (1)
and ds/di
was obtained. The average particle size of the hard phase was defined as an
average
value of the average particle size ds in the surface region and the average
particle size di
in the internal region. The ds/di and the average particle size of the hard
phase are
shown in Table 5. Further, from the image thus taken, the area ratio Cls of
the core
portion in the first hard phase in the surface region and the area ratio Cli
of the core
portion in the first hard phase in the internal region were measured using
Fullman's
expression (1). Cis/Cli was obtained from Cis and Cli that were measured. The
results are shown in Table 5.
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[0053] [Table 5]
Average Particle Size of
Sample No. ds/di Cls/Cli
Hard Phase (gm)
Present Product 1 1.3 1.5 0.8
Present Product 2 1.1 1.2 0.9
Present Product 3 1.6 1.8 0.5
Present Product 4 1.3 1.4 0.8
Present Product 5 1.4 1.6 0.7
Present Product 6 1.7 1.7 0.8
Present Product 7 1.2 1.3 0.7
Present Product 8 1.5 1.7 0.3
Present Product 9 1.0 1.3 0.9
Present Product 10 1.3 1.6 0.7
Comparative Product 1 1.8 3.2 0.5
Comparative Product 2 1.7 0.9 0.7
Comparative Product 3 2.1 1.4 0.4
Comparative Product 4 1.0 1.2 1.0
Comparative Product 5 2.2 2.2 0.5
Comparative Product 6 2.5 1.8 1.1
[0054] For the polished surface polished by tilting at 10 degrees relative to
the surface
of the cermet tool, Vickers hardness at an applied load of 4.9 N was measured
using a
micro-Vickers hardness tester with intervals of 10 gm in a vertical direction
from the
surface of the cermet tool. The maximum hardness within a range within 300 gm
from
the surface of the cermet tool was defined as Hs. Vickers hardness in 5 spots
in
positions of 500 gm from the surface of the cermet tool was measured and the
maximum hardness in the 5 spots was defined as Hi. The results are shown in
Table 6.
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[0055] [Table 6]
Sample No. Hs/Hi
Present Product 1 1.1
Present Product 2 1.1
Present Product 3 1.3
Present Product 4 1.1
Present Product 5 1.1
Present Product 6 1.3
Present Product 7 1.1
Present Product 8 1.3
Present Product 9 1.1
Present Product 10 1.1
Comparative Product 1 1.4
Comparative Product 2 1.0
Comparative Product 3 1.4
Comparative Product 4 1.3
Comparative Product 5 1.4
Comparative Product 6 1.3
[0056] The cermet tools of Present Products and Comparative Products were
polished
vertically to the surfaces of the cermet tools, and from the cross-sections of
the polished
surfaces, the composition of each hard phase was identified by the SEM with an
EDS.
Further, an image of the cross-section of the internal region of the ceiniet
tool enlarged
at a magnification of 10000 with the SEM was taken. From the image thus taken,
the
area ratios Al, A2, and A3 of the respective hard phases were obtained using
commercially available image analysis software. The results are shown in Table
7.
Then, a cross-section to 500 pm inside in the depth direction from the surface
of the
cermet tool was observed with an SEM with an EDS to identify the composition
of the
binder phase. Further, the cross-section was chemically etched using aqua
regia to
observe the chemically etched cross-section with the SEM with an EDS. Then,
from
these two types of cross-section, an area ratio of the hard phase that was not
chemically
etched and an area ratio of binder phase that was chemically etched were
measured.
From the results, the proportion of volume% of the hard phase and volume% of
the
binder phase in the cermet tool were obtained. The results are shown in Table
8.
[0057] [Table 7]
Hard Phase
First Hard Phase Second Hard Phase Third Ilard Phase
Sample No. Composition Composition
Composition
_______________________________________________________________________________
______ A I _______________ A2 A3
Core Portion Peripheral Portion (area%) Core
Portion Peripheral Portion (area%) Single Phase (area%)
Particle
_______________________________________________________________________________
______________________
Present
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 85 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 6 (Ti, Nb, Mo) (C, N) 9
Product 1
Present
Product 2 (Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N)
80 (Ti, Nb, Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 4 (Ti, Nb,
Mo) (C, N) 18
Present
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 88 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 10 (Ti, Nb, Mo) (C, N) 2
Product 3
Fresent
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 84 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 7 (Ti, Nb, Mo) (C, N) 9
Product 4
Present
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 86 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 6 (Ti, Nb, Mo) (C, N) 8
Product 5
Present
(Ti, Nb, Mo) (C, N) Nb, Mo, W, Zr) (C, N) 91 (Ti, Nb,
Mo, W) (C, N) Nb, Mo, W, Zr) (C, N) 7 (Ti, Nb, Mo) (C, N)
2
Product 6
Present
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 83 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 10 Nb, Mo) (C, N) 7
0
Product 7
Present
Product 8 (Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 84
(Ti, Nb, Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 6 (Ti, Nb, Mo)
(C, N) 10
Present
(11, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 85 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 7 (Ti, Nb, Mo) (C, N) 8
Product 9
Present (Ti, Nb, Ta, Mo) (C, (Ti, Nb, Ta, Mo, W,
Zr) (C, (Ti, Nb, Ta, Mo, W) (C, (Ti, Nb, Ta, Mo, W, Zr) (C,
(Ti, Nb, Ta, Mo) (C,
82
8 10
Product 10 N) N) N)
N) __ N)
Comparative
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 73 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 27
Product 1
Comparative
Nb, Mo) (C, N) (Ti, NU, Mo, W, Zr) (C, N) 66 (Ti, Nb,
Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 34 0
Product 2
C Hard Phase having Core Portion of "Ti (C, N) and
Peripheral Portion of (Ti, Nb, Mo, W, Zr) (C, N): 78 area%
omparative
Hard Phase having Core Portion a(Ti, Nb, Mo, W) (C, N) and Peripheral Portion
of (ft, Nb, Mo, W, Zr) (C, N): 11 area%
Product 3
Hard Phase or Ti (C, N): 11 area%
Comparative
Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 91 Nb, Mo, W)
(C, N) (Ti, Nb, Mo, W, Zr) (C, N) 9 0
Product 4
Comparative
(Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 70 (Ii, Nb,
Mo, W) (C, N) (II, NU, Mu, W, Zr) (C, N) 30 0
Product 5 ________________
Comparative
Product 6 (Ti, Nb, Mo) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 85
(Ti, Nb, Mo, W) (C, N) (Ti, Nb, Mo, W, Zr) (C, N) 6 (Ti, Nb, Mo)
(C, N) 9
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[0058] [Table 8]
Hard Phase Binder Phase
Sample No.
(volume /) Composition (volume%)
Present Product 1 86.4 (Ti, W) (Co, Ni) 13.6
Present Product 2 86.5 (Ti, W) (Co, Ni) 13.5
Present Product 3 86.1 (Ti, W) (Co, Ni) 13.9
Present Product 4 86.4 (Ti, W) (Co, Ni) 13.6
Present Product 5 86.4 (Ti, W) (Co, Ni) 13.6
Present Product 6 90.3 (Ti, W) (Co, Ni) 9.7
Present Product 7 80.8 (Ti, W) (Co, Ni) 19.2
Present Product 8 86.2 (Ti, W) (Co, Ni) 13.8
Present Product 9 86.4 (Ti, W) (Co, Ni) 13.6
Present Product 10 86.3 (Ti, W) (Co, Ni) 13.7
Comparative Product 1 86.5 (Ti, W) (Co, Ni) 13.5
Comparative Product 2 86.6 (Ti, W) (Co, Ni) 13.4
Comparative Product 3 86.9 (Ti, W, Nb) (Co, Ni) 13.1
Comparative Product 4 86.1 (Ti, W) (Co, Ni) 13.9
Comparative Product 5 86.8 (Ti, W) (Co, Ni) 13.2
Comparative Product 6 86.5 (Ti, W) (Co, Ni) 13.5
[0059] Using the samples thus obtained, Cutting Test 1, Cutting Test 2, and
Cutting
Test 3 were performed. Cutting Test 1 is a test for evaluation of fracture
resistance,
Cutting Test 2 for evaluation of wear resistance, and Cutting Test 3 for
evaluation of a
machined surface of a work piece material. The results of Cutting Tests are
shown in
Table 9.
[0060] [Cutting Test 1]
Processing mode: Milling,
Tool shape: SDKN1203,
Work piece material: SCM440,
Shape of work piece material: 200 mm x 80 mm x 200 mm (shape: board material
with
six holes of 30 mm size),
Cutting speed: 150 m/min,
Feed: 0.25 mm/tooth,
Depth of cut: 2.0 mm,
Coolant: Not used,
Point of evaluation: the tool life was defined as the time when the sample has
a fracture,
and the length of process until tool life was measured.
[0061] [Cutting Test 2]
Processing mode: Milling,
Tool shape: SDKN1203,
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Work piece material: SCM440,
Shape of work piece material: 200 mm x 80 mm x 200 mm,
Cutting speed: 250 muffin,
Feed: 0.15 mm/tooth,
Depth of cut: 2.0 mm,
Coolant: Not used, and
Point of evaluation: the tool life was defined as the time when the sample has
a fracture
or the sample has 0.3 mm of maximum flank wear width or the corner wear width,
and
the length of process until tool life was measured.
[0062] [Cutting Test 3]
Processing mode: Milling,
Tool shape: SDKN1203,
Work piece material: SS400,
Shape of work piece material: 150 mm x 70 mm x 150 mm,
Cutting speed: 150 m/min,
Feed: 0.15 mm/tooth,
Depth of cut: 0.3 mm,
Coolant: Not used, and
Point of evaluation: the arithmetic mean roughness Ra of the process surface
of the
work piece material was evaluated when the length of process was 5.0 m.
CA 02943181 2016-09-19
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[0063] [Table 9]
Cutting
Cutting Test 2 Cutting Test 3
Test 1
Fracture
Machined surface
Resistance Wear Resistance Test
Sample No. Evaluation Test
Test
Surface Roughness of
Tool Life Tool Life Mode of
Work Piece Material
(m) (m) Damage
Ra (Jim)
Present
3.5 12.8 Flank Wear 0.12
Product 1
Present
3.0 13.5 Flank Wear 0.11
Product 2
Present
3.8 11.4 Flank Wear 0.16
Product 3
Present
3.2 11.2 Flank Wear 0.13
Product 4
Present
3.3 12.4 Flank Wear 0.14
Product 5
Present
2.9 14.1 Flank Wear 0.11
Product 6
Present
4.2 9.8 Flank Wear 0.14
Product 7
Present
3.0 13.0 Flank Wear 0.12
Product 8
Present
3.6 9.5 Flank Wear 0.14
Product 9
Present
3.7 12.9 Flank Wear 0.12
Product 10
Comparative
2.1 9.2 Flank Wear 0.26
Product 1
Comparative
1.8 6.3 Flank Wear 0.17
Product 2
Comparative
0.7 5.8 Fracture 0.32
Product 3
Comparative
2.2 2.7 Flank Wear 0.37
Product 4
Comparative
0.8 11.2 Flank Wear 0.22
Product 5
Comparative
1.1 13.0 Flank Wear 0.19
Product 6
[0064] The length of process in Cutting Test 1 was evaluated as "0" for 3 m or
more,
"0" for not less than 2 m and less than 3 m, "A" for not less than 1 m and
less than 2 m,
and "X" for less than 1 m. The length of process in Cutting Test 2 was
evaluated as
"0" for 10 m or more, "0" for not less than 7 m and less than 10 m, "A" for
not less
CA 02943181 2016-09-19
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than 3 m and less than 7 m, and "X" for less than 3 m. The arithmetic mean
roughness
Ra of the process surface of the work piece material in Cutting Test 3 was
evaluated as
"0" for less than 0.15 m, "0" for not less than 0.15 p.m and less than 0.25
m, "A" for
not less than 0.25 pm and less than 0.35 m, and "X" for 0.35 jim or more. The
evaluation is in the order of (excellent) "0"> "0"> "A" > "X" (poor), and "0"
and "0"
show better cutting performances. The results of evaluation thus obtained are
shown
in Table 10.
[0065] [Table 10]
Sample No. Cutting Test 1 Cutting Test 2 Cutting Test 3
Present Product 1 0 0
Present Product 2 0 0
Present Product 3 0 0 0
Present Product 4 0 0 0
Present Product 5 0 0
Present Product 6 0 0 0
Present Product 7 0 0 0
Present Product 8
Present Product 9 0 0 0
Present Product 10 0 0 0
Comparative Product 1 0 0 A
Comparative Product 2 A A 0
Comparative Product 3 X A A
Comparative Product 4 0 X X
Comparative Product 5 X 0 0
Comparative Product 6 A 0 0
[0066] All of the evaluations of Present Products were "0" or "0", and it is
understood that they were excellent in wear resistance and fracture resistance
and were
capable of reducing the machined surface roughness. In contrast, the
evaluations of
Comparative Products have "A" or "X", and it is understood that they did not
satisfy at
least one of the performances among wear resistance, fracture resistance, and
machined
surface roughness.
Example 2
[0067] The surfaces of the cermet tools of Present Products 1 to 10 in Example
1 were
coated using a PVD apparatus. Present Products 1 to 10 and Comparative
Products 1
to 6 were coated with a TiA1N layer having an average layer thickness of 2.5
m on the
surfaces and they are defined as Present Products 11 to 20 and Comparative
Products 7
to 12. The cermet tool of Present Product 1 was coated with a Ti (C, N) layer
having
CA 02943181 2016-09-19
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an average layer thickness of 2.5 pm on the surface and it is defined as
Present Product
21. In addition, the cermet tool of Present Product 1 was coated with an
alternate
lamination in which TiAlN with 2 nm per layer and TiAlNbWN with 3 nm per layer
were alternately laminated 500 layers each and it is define as Present Product
22.
Present Products 11 to 22 and Comparative Products 7 to 12 were subjected to
Cutting
Tests 1, 2, and 3, which are the same as the Tests in Example 1. The results
are shown
in Table 11.
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[0068] [Table 11]
Cutting Test 1 Cutting Test 2 Cutting Test 3
Fracture
Machined surface
Resistance Wear Resistance Test
Evaluation Test
Sample No. Test
Mode of Surface Roughness of
Tool Life Tool Life
Damage Work Piece Material Ra
(m) (m)
Present
3.1 17.4 Flank Wear 0.19
Product 11
Present
2.8 19.0 Flank Wear 0.18
Product 12
Present
3.2 13.5 Flank Wear 0.24
Product 13
Present
2.5 13.5 Flank Wear 0.17
Product 14
Present
2.8 15.4 Flank Wear 0.19
Product 15
Present
2.2 16.8 Flank Wear 0.14
Product 16
Present
3.1 11.1 Flank Wear 0.15
Product 17
Present
2.5 14.2 Flank Wear 0.17
Product 18
Present
3.1 10.8 Flank Wear 0.21
Product 19
Present
3.3 17.6 Flank Wear 0.19
Product 20
Present
2.8 18.2 Flank Wear 0.19
Product 21
Present
3.3 19.8 Flank Wear 0.15
Product 22
Comparative
1.4 11.2 Flank Wear 0.33
Product 7
Comparative
0.9 8.7 Flank Wear 0.25
Product 8 ___________________________________________________________
Comparative
0.3 7.4 Fracture 0.42
Product 9 __
Comparative
1.2 3.3 Flank Wear 0.47
Product 10
Comparative
0.2 13.3 Flank Wear 0.36
Product 11
Comparative
0.1 15.0 Flank Wear 0.55
Product 12
[0069] The length of process in Cutting Test 1 was evaluated as "0" for 3 m or
more,
"0" for not less than 2 m and less than 3 m, "A" for not less than 1 m and
less than 2 m,
CA 02943181 2016-09-19
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and "X" for less than 1 m. The length of process in Cutting Test 2 was
evaluated as
"0" for 10 m or more, "0" for not less than 7 m and less than 10 m, "A" for
not less
than 3 m and less than 7 m, and "X" for less than 3 m. The arithmetic mean
roughness
Ra of the process surface of the work piece material in Cutting Test 3 was
evaluated as
"0" for less than 0.15 J.im, "0" for not less than 0.15 m and less than 0.25
pm, "A" for
not less than 0.25 1.,im and less than 0.35 mn, and "X" for 0.35 pm or more.
The
evaluation is in the order of (excellent) "0" > "0" > "A" > "X" (poor), and
"0" and "0"
show better cutting performances. The results of evaluation thus obtained are
shown
in Table 12.
[0070] [Table 12]
Sample No. Cutting Test 1 Cutting Test 2 Cutting Test 3
Present Product 11 0
Present Product 12 0 0
Present Product 13 0 0
Present Product 14 0 0
Present Product 15 0 0
Present Product 16 0 0
Present Product 17 0 0
Present Product 18 0 0
Present Product 19 0
Present Product 20 C:) 0
Present Product 21 0 0 0
Present Product 22 0 0
Comparative Product 7 A 0 A
Comparative Product 8 X 0 A
Comparative Product 9 X 0 X
Comparative Product 10 A A X
Comparative Product 11 X X
Comparative Product 12 X 0 X
[0071] All Present Products of the evaluations of Present Products were "0" or
"0",
and it is understood that they were excellent in wear resistance and fracture
resistance
and were capable of reducing machined surface roughness. In contrast, the
evaluations
of Comparative Products have "A" or "X", and it is understood that they did
not satisfy
at least one of the performances among wear resistance, fracture resistance,
and
machined surface roughness. In the wear resistance test, the tool life of
Present
Products without coating a coating layer was 9.5 m or more, whereas the tool
life of
Present Products with coating a coating layer was 10.8 m or more. Therefore,
it is
understood that the tool life became longer. Present Products 11 to 22 with
coating a
coating layer had smaller surface roughness compared to that of Comparative
Products
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7 to 12 and enabled that life time in wear resistance was longer than that of
Present
Products 1 to 10 without coating a coating layer.
Industrial Applicability
[0072] The coated cutting tool of the present invention is capable of reducing
machined surface roughness of a work piece material and is excellent in
fracture
resistance and chipping resistance without reducing wear resistance.
Therefore, the
tool is capable of extending tool life more than conventional ones, so that
the coated
cutting tool of the present invention is highly industrially applicable.
